The present invention relates to a relaxation apparatus and a method for providing relaxation and recreation for a person by applying a vibratory stimulus to the person.
It has long been well known that as a cradle or a rocking chair makes it clear, a person can feel relaxed when cyclically oscillated moderately. The Japanese Laid-open Patent Publication No. 4-216743, published Aug. 6, 1992, discloses a vibrating floor system comprising a flat support accommodated within a recess defined in a floor in flush with the floor and isolated from the floor. The flat support is oscillatably supported by means of a plurality of spring members and is adapted to be vibrated in two directions perpendicular to each other by means of respective vibrating mechanisms according to a predetermined pattern of vibration selectable through a control device.
It is well known that vibration applied to a local portion of a human body is sensed by acceleration sensitive receptors found on the skin. However, moderate oscillation or vibration applied to the whole body of a human being is detected mainly by cerebellum and semicircular canals. Accordingly, by oscillating or vibrating the whole body of the person moderately, it is rather feasible to lead the person to relaxation. Since the flat support disclosed in the above mentioned publication is used to support thereon the whole body of the person who desires relaxation, it appears that the vibrating floor system is satisfactory. However, it has been found that mere application of the vibration to the body of a human being does not necessarily lead to relaxation and will often provide an uncomfortable sensation to the person.
U.S. Pat. No. 3,532,089 issued Oct. 6, 1970 to Arntzenius discloses a bed or table supporting the body of a patient for reciprocation generally along the vertical or long dimension of the heart of the patient synchronously with the heartbeat that is sensed by a heartbeat sensor. With this bed or table, the patient""s body is described accelerated rhythmically and synchronously with heartbeat, with varying degrees of magnitude (from 0 to 3 g) and duration (0 to 100 msec) of acceleration.
According to Arntzenius"" patent, the bed is reciprocated in a direction generally along the vertical or long dimension of the heart of the patient, which corresponds to the lengthwise direction of the bed as viewed with the patient lying on the bed. While Arntzenius is silent as to the specific frequency of vibration of the bed, it describes that the patient""s body on the bed is accelerated rhythmically and synchronously with the heartbeat, with varying degrees of magnitude from 0 to 3G and duration of 0 to 100 msec of acceleration. Assuming that the heartbeat is 65 per minute, the frequency of vibration synchronized with the heartbeat may correspond to about 1.8 Hz. However, Arntzenius"" patent is directed to the bed for aiding cardiovascular circulation and is in no way related to the relaxation apparatus.
U.S. Pat. No. 4,133,305 issued Jan 9, 1979 to Steuer discloses a relaxation apparatus including a mattress consisting essentially of an inflatable hollow body defining an interior space and having an upper reclining surface area for carrying a human body. According to this patent, an air pump is connected to the hollow body for inflating it with air. A vibrating device cooperates with the pump for periodically varying the pressure in the interior space at a preselected frequency so as to raise and lower the reclining surface area periodically. The vibrating device includes a control system for varying the preselected frequency within a range containing the respiration rates. The control system may include means for varying the amplitude of the periodic pressure variations.
U.S. Pat. No. 3,826,250 issued Jul. 12, 1972 to Adams discloses a relaxation apparatus comprising an upholstered seat accommodated within a housing for permitting a person to recline on the seat, a pair of rockers supporting the housing and adapted to be driven by a drive unit for driving the rockers to rock the housing, a vibrator connected to the seat for vibrating a person on the seat, and one or a plurality of sensory stimulators. The sensory stimulators useable in this relaxation apparatus are described including loudspeakers or earphones for providing aural stimuli, one or more displays for providing visual stimuli, food materials for providing gustatory stimuli, a scent generator for providing olfactory stimuli, and so on.
U.S. Pat. No. 4,586,492 issued May 6, 1986 to Manahan discloses a therapeutic bed comprising upper, intermediate and lower frame structures all drivingly coupled with each other. Specifically, the upper frame structure is pivotable about its central longitudinal axis with respect to the intermediate frame structure which is also pivotable about its central longitudinal axis with respect to the lower frame structure. Independent mechanical means having variable speed controls each employ a rotating eccentric arm which oscillates the respective pivotable frame structure so that the bed itself can oscillate in a circular rhythmic fashion, most nearly analogized to a boat at anchor rolling in a gentle sea.
A bed similar to that disclosed in U.S. Pat. No. 4,586,492, but movable in a circular or rotary path only in a vertical plane is disclosed in U.S. Pat. No. 5,301,661 issued Apr. 12, 1994 to Lloyd.
U.S. Pat. No. 2,570,676 issued Oct. 9, 1951 to Henderson discloses a reciprocating bed comprising a bed support capable of being oscillated in a direction perpendicular to the longitudinal sense of a human body lying on a mattress which is mounted on the bed support through a plurality of coiled springs. This patent describes that best results would be brought about when the bed support is reciprocated in length (i.e., vibrating amplitude) from xe2x85x9 to 18 inches (about 3 to 460 mm) and/or at a rate of 24 to 800 strokes per minute (corresponding to a vibration frequency of about 0.4 to 13 Hz).
A vestibular motion table disclosed in U.S. Pat. No. 5,520,614 issued May 28, 1996 to McNamara et al. is generally similar to the bed disclosed in Henderson""s USP discussed above. This patent describes that best results would be brought about when he vestibular motion table is cyclically in a direction longitudinally thereof about xc2xd inch in each cycle (corresponding to a vibrating amplitude of about 13 mm) and/or at a frequency of 0 to 200 cycles per minute (corresponding to 0 to 3.3 Hz).
The present invention has been devised to provide an improved relaxation apparatus effective to positively bring the person into a state of relaxation.
To this end, in accordance with a broad aspect of the present invention, a relaxation apparatus which includes a support means for supporting a whole body of a person who desire relaxation. The support means is employed in the form of a reclining chair having a seat, a seatback tiltable relative to the seat, and a footrest tiltable to the seat. A vibrating means is employed to vibrate the support means to vibrate the whole body of the person at a frequency not higher than 25 Hz. A control means controls the vibrating means such that the maximum acceleration of the vibration produced by the vibrating means to vibrate the person supported on the support means is not greater than 0.1 G. Specifically, the control controls the acceleration in dependence on the frequency of vibrations outputted by the vibrating means such that said acceleration is small when the frequency of vibrations outputted by the vibrating means is low while the acceleration is large when the frequency of vibrations is high.
Preferably, the vibrating means has a capability of vibrating the support means selectively in at least first and second planes perpendicular to each other, and wherein the vibration applied from the vibrating means to the support means and then to the body of the person is such that a portion of the body of the person adjacent the waist will not be excessively pulled rearwards with respect to a position at which the vibrating means is started.
The support means may be supported by a base. In this case, to enable the person resting on the support means to be quickly led to relaxation, the vibration applied from the vibrating means to the support means and then to the body of the person is preferably of a kind that the head of the person being vibrated can move while depicting a straight path or a downwardly curved path, and/or a portion of the body of the person adjacent the waist will not be pulled rearwards more than a prescribed level.
Preferably, the vibration produced by the vibrating means acts directly on the whole body of the person and wherein said support means is movable in a direction conforming to a direction of propagation of vibrations transmitted by the vibrating means to the person.
The relaxation apparatus may further include a relaxation sensor for detecting the degree of relaxation enjoyed by the person with its output used to vary a pattern of the vibration produced by the vibrating means, and/or at least one additional vibrating means for vibrating a local portion of the body of the person, and/or at least one of a heating means for heating the body of the person, a cooling means for cooling the body of the person, at least one auxiliary stimulus means for applying an auxiliary stimulus to the person in synchronism with the vibration, and a massaging means for massaging a local portion of the body of the person.
Preferably, one or both of the frequency and the acceleration are variable according to a pattern of vibration applied to the person.
The vibrating means utilizable in the practice of the present invention may be of a type capable of cyclically vibrating the support means in a single plane, or may be of a type capable of cyclically vibrating the support means in two plans perpendicular to each other. In the latter case, the acceleration represents a rotational acceleration having vector components acting in respective directions perpendicular to each other and the maximum value of which is preferably the maximum rotational acceleration.
The reclining chair forming the support means comprises a seat, a seatback tiltable relative to the seat at an angle of about 90xc2x0 to about 180xc2x0 and a footrest tiltable relative to the seat at an angle of about 90xc2x0 to about 180xc2x0. As a matter of course, when the seatback and the footrest are set at respective 180xc2x0 positions relative to the seat, the reclining chair as a whole represents a configuration similar to a bed. Preferably, the reclining chair may be of an electrically powered reclining chair in which one or both of the seatback and the foot rests are electrically powered to tilt.
In another preferred embodiment of the present invention, the relaxation apparatus may further comprises an additional vibrating device such as, for example, at least one massaging device for massaging a localized area of the body of the person desiring relaxation. In addition to or separate therefrom, a cooling means and/or a heating means may be employed together with or separate from an auxiliary stimulating means for applying an auxiliary stimuli to the body of the person synchronously with the vibration applied thereto.
If the upper limit of the absolute value of the acceleration exceeds 0.1 G, most of the people will feel uncomfortable and/or unbearable. By way of example, FIG. 5 illustrates how people being vibrated entirely at a varying frequency would feel with change in effective value of the vibratory acceleration. The graph of FIG. 5 is reproduced from a book entitled xe2x80x9cNingen-Kogaku Gairon (Introduction to Human Engineering)xe2x80x9d published from Asakura Shoten. In this graph, a curved band A represents the region of vibrations the average people can bear; a curved band B represents the region of vibrations the average people feel uncomfortable; and a curved band C represents a region of threshold of the vibratory stimulus.
The effective value of the acceleration may be about 0.0001 G. This value of 0.0001 G is far smaller than that shown in the graph of FIG. 5. However, according to the graph of FIG. 6 in which an objective evaluation (i.e., 95% reliable region of the acceleration felt comfortable by people) is shown as a result of investigation carried out by the inventors, the vibration at an acceleration in the order of 10xe2x88x924 G could be felt comfortable so long as the vibration is of a relatively low frequency, especially not higher than 1 Hz. Although the vibration is barely felt by persons if the acceleration is smaller than 0.0001 G, some people may be brought into a relieved state depending on the vibratory frequency even though no vibration is sensed.
According to the present invention, the vibrating means is preferably capable of vibrating the support means at a frequency corresponding to the eigen (proper) vibration of a railway car that is lower than 25 Hz, with an acceleration of a magnitude corresponding to 1.5 or less of the coefficient of railway riding comfort. As discussed in xe2x80x9cShindou Kougaku Handobukku (Handbook of Vibration Engineering)xe2x80x9d, pp 1144-1146, published 1991 from Kabushiki Kaisha Yokendo of Japan, the proper vibration of the railway car that is lower than 25 Hz is made up of a low frequency vibration (not higher than 2 Hz) and a high frequency vibration (7 to 13 Hz) both acting in a horizontal direction perpendicular to the length of the railway car and a low frequency vibration (1 to 3 Hz) and a high frequency vibration (8 to 13 Hz) both acting in a vertical direction perpendicular to the length of the railway car.
Also, according to the handbook, supra, the proper vibration of an ordinary railway bogie car includes a linear vibration represented by cyclic movement in a direction conforming to the length of the bogie car, a vertical vibration represented by cyclic movement in a vertical direction perpendicular to the length of the bogie car, a horizontal vibration represented by cyclic movement in a horizontal direction perpendicular to the length of the bogie car, and rotatory vibrations such as rolling, yawing and pitching. The proper value of the linear vibration is considered to be within the range of 1.5 to 2.5 Hz, that of the vertical vibration is considered to be within the range of 1 to 3 Hz and that of the horizontal vibration is considered to be not higher than 2.0 Hz. Other than those vibrations, the bogie car exhibits a flexing vibration of 8 to 13 Hz commonly in those directions, and in all cases, the newer the railway car, the lower the frequency of vibration.
Relationships between the railway riding comfort and the vibrating characteristics of the railway car acting in respective directions are shown in FIGS. 36A to 36C. Referring to these figures, at a low frequency region not higher than 3 Hz that can be perceived by the sense of proportion, the linear vibration acting in a direction conforming to the length of the railway car is of such a low level as compared with that acting in any other direction that the linear vibration will not almost affects the riding comfort. However, 5 to 10 Hz region of the linear vibration is associated with the riding comfort and it has been found that the lower the level of this vibration, the higher the riding comport. Also, if the frequency of vibration of the railway car exceeds 25 Hz, passengers on the railway car will feel uncomfortable even though the acceleration is low and will therefore find difficulty relaxing.
In view of the foregoing, in the practice of the present invention, the support means is vibrated at a frequency which is not higher than 25 Hz in the horizontal (leftwards and rightwards) direction perpendicular to the longitudinal sense of the body of the person desiring relaxation and which, as far as the vertical (up and down) direction is concerned, corresponds to the level of acceleration corresponding to 1.5 or less of the riding comfort of the railway car. As a result thereof, the person can be led to relaxation without feeling any discomfort which would be brought about by velocity and vibration.
By the reasons discussed hereinabove, the vibrating means is so designed as to apply the vibration of a frequency not higher than 25 Hz. However, considering that people have their own personal preference, the frequency of vibration applied from the vibrating means to the support means is preferably not higher than 12 Hz.
In order to render the relaxation apparatus to accommodate preference of the user which may vary from person to person, the vibratory frequency and/or the effective acceleration may preferably be adjustable. Change in vibratory frequency and/or effective acceleration may be automatically accomplished either according to the length of time passed, a 1/f fluctuation pattern or the number of cycles of vibration. Alternatively, it may be accomplished manually by the user. In particular, where one or both of the vibratory frequency and the effective acceleration are desired to be changed or adjusted according to the length of time passed or the number of times of application of the vibration (i.e., the number of times of use of the apparatus), this can be accomplished by the use of a timer or a number-of-use presetting device. Where one or both of the vibratory frequency and the effective acceleration is desired to be changed or adjusted according to the 1/f fuzzy scheme, it can be implemented by the use of a computer executable software that causes the vibrating means to produce a pattern of 1/f fuzzy vibration. Again, design may be made that one or both of the vibratory frequency and the effective acceleration can be gradually reduced according to the length of time passed or the number of times of application of the vibration, so that the person on the support means can be smoothly led to relaxation.
To apply vibration to the body of the person on the support means involves the body of the person being cyclically shifted forwards and backwards. Accordingly, a zero-velocity condition will occur for a considerably slight length of time at the time of reversal of one of the forward shift and the backward shift to the other. The shorter the duration of the zero-velocity condition, the better. By way of example, if the duration of the zero-velocity condition will be about 500 msec, it is not proper since the person will feel discontinuity of the cyclic movement.
Also, the use may also be made of a relaxation sensor for detecting the degree of relaxation enjoyed by the person, an output from said relaxation sensor being used to vary the pattern of vibration produced by the vibrating means. Specifically, depending on the degree of relaxation detected by the relaxation sensor, the vibrating means may be brought to a halt or may be set in a predetermined vibrating mode and/or an awaking stimulus may be applied to the person being oscillated. This is particularly advantageous where the user resting on the support means begins to sleep.
The use of the relaxation sensor may not be essential in the practice of the present invention, in which case the relaxation apparatus may be so designed that upon passage of a predetermined length of time of use of the apparatus or increase of the number of times of use of the apparatus over a predetermined value, the vibrating means can be brought to a halt or be operated under a predetermined vibrating mode, and/or an awaking stimulus can be applied to the person being relaxed.
The relaxation apparatus of the present invention may also comprise one or all of a heating means for heating the body of the person, a cooling means for cooling the body of the person, an auxiliary stimulus means for applying an auxiliary stimulus to the person in synchronism with the vibration, and a massaging means for massaging a local portion of the body of the person.
Preferably, regardless of the use of the heating means, the cooling means and the auxiliary stimulus means, the reclining chair employed for the support means is preferably in the form of an electrically powered reclining chair having the seatback and the foot rest that can be electrically driven to assume a horizontal position generally in flush with the seat to render the reclining chair to assume a substantially full flat position. Setting the reclining chair in the full flat position may be made in response to the degree of relaxation sensed by the relaxation sensor, passage of the predetermined length of time of use of the apparatus and/or increase of the number of times of use over the predetermined value. This feature is particularly advantageous in that the seat occupant being relaxed can readily feel at easy with increase of the degree of relaxation.
The present invention also provides a method of relieving a person desiring relaxation. This method comprises the steps of preparing a support means for supporting thereon a whole body of the person; vibrating the support means to vibrate the whole body of the person; and controlling the vibrating means to generate vibrations of a frequency not higher than 25 Hz with the maximum absolute value of acceleration of the vibration being not greater than 0.1 G.
In the practice of the present invention, the vibration produced by the vibrating means may be applied to the body of the person in any desired manner and in any desired mode. By way of example, where the support means comprises a reclining chair of the type referred to hereinbefore, i.e., that having a tiltable seat back and a tiltable footrest, the reclining chair as a whole may be vibrated in one or a combination of any desired directions including an x-axis direction conforming to the longitudinal sense of the body of the person, a y-axis direction perpendicular to the longitudinal sense of the body of the person and also to the x-axis direction, a z-axis direction perpendicular to any of the x-axis and y-axis directions and a combination thereof.
On the other hand, where the support means comprises the reclining chair of a type that is suspended by a stand for cyclic rocking motion in a direction conforming to the longitudinal sense of the body of the person, the vibrating means may be of a type capable of cyclically pushing the reclining chair from rear of the tiltable seatback.
In any event, in accordance with the present invention, it is essential that the frequency of vibrations applied to the body of the person occupying the support means should not exceed 25 Hz with the acceleration not greater than 0.1 G and variable in dependence on the frequency of vibrations. Specifically, the acceleration may be small or large when the frequency of vibrations is low or high, respectively. Thus, in the present invention, the frequency of vibrations and the acceleration are correlated with each other.